Recently, demands for a high-resolution and high-quality image have increased in various fields of applications. As an image has higher resolution and higher quality, an amount of information on the image increases more. Accordingly, when image information is transferred using media such as existing wired or wireless broadband lines or image information is stored in existing storage media, the information transfer cost and the information storage cost increase. Therefore, high-efficiency image compressing techniques can be used to effectively transfer, store, and reproduce information on high-resolution and high-quality images.
Inter prediction and intra prediction can be used to enhance image compression efficiency.
In the inter prediction, pixel values of a current picture are predicted from temporally previous and/or subsequent pictures. In the intra prediction, pixel values of a current picture are predicted using pixel information in the current picture.
In addition to the inter prediction and the intra prediction, a weighting value predicting technique for preventing degradation in image quality due to a variation in illumination or the like, an entropy encoding technique of assigning a short code to a symbol with a high appearance frequency and assigning a long code to a symbol with a low appearance frequency, and the like can be used for more efficiently processing image information.